Can I Eat Tuna While Pregnant? (Mercury Limits Explained)

Quick Answer

Yes, you can eat tuna during pregnancy—but the type and amount matter significantly. Tuna is one of the most consumed fish worldwide, and for good reason: it is affordable, widely available, and packed with nutrients your growing baby needs. However, because tuna accumulates mercury through the marine food chain, pregnant women need to be strategic about which varieties they choose and how often they enjoy them.

The good news? With a little knowledge, you can safely include tuna in your pregnancy diet while reaping its impressive nutritional benefits.

Why This Matters: Mercury and Your Baby

Mercury is a naturally occurring heavy metal that enters our waterways through industrial pollution and natural processes. Fish absorb mercury from the water and their food sources, and larger, longer-lived predatory fish—like certain tuna species—accumulate higher concentrations over time. This process is called bioaccumulation.

During pregnancy, mercury can cross the placental barrier and affect your baby's developing nervous system. According to research published in the Journal of Preventive Medicine and Public Health, prenatal mercury exposure has been associated with subtle effects on cognitive development, memory, and attention in children. However—and this is important—these effects are primarily seen at high exposure levels, not from moderate fish consumption within recommended guidelines.

The key insight from decades of research is this: the nutritional benefits of fish often outweigh the risks when you choose lower-mercury varieties and stay within serving limits. A 2024 systematic review in Nutrients found that pregnant women who consumed 2-3 servings of low-mercury fish weekly had babies with better neurodevelopmental outcomes than those who avoided fish entirely.

Understanding Tuna Types: A Mercury Comparison

Not all tuna is created equal when it comes to mercury content. Here is what the research shows:

As you can see, canned light tuna contains nearly three times less mercury than albacore. This difference matters significantly when planning your weekly fish intake.

How Much Tuna Can You Safely Eat?

Major health organisations provide consistent guidance on fish consumption during pregnancy. The UK NHS, US FDA, and ACOG all recommend that pregnant women consume 2-3 servings (about 225-340g total) of low-mercury fish per week for optimal omega-3 benefits.

Here is how that translates specifically to tuna:

A real-life example: Sarah, a mum in her second trimester, loves her tuna sandwiches. She switched from albacore to canned light tuna and now comfortably enjoys two tuna salads per week alongside a salmon dinner—staying well within safe limits while getting excellent omega-3s for her baby's brain development.

The Omega-3 Trade-Off: Why Fish Matters

Here is something many articles fail to mention: avoiding fish entirely during pregnancy may be more harmful than eating it wisely. Fish, including tuna, is one of the best dietary sources of DHA (docosahexaenoic acid)—an omega-3 fatty acid critical for your baby's brain and eye development.

Research published in the American Journal of Clinical Nutrition found that infants born to mothers with higher DHA intake during pregnancy showed improved visual acuity and cognitive performance at 4-6 months of age. Another landmark study from Harvard tracked over 12,000 mother-child pairs and found that children whose mothers ate more than two fish servings weekly during pregnancy had higher IQ scores and better fine motor skills at age 3.

A 140g serving of canned light tuna provides approximately 200-300mg of omega-3s—contributing meaningfully toward the 200-300mg DHA recommended daily during pregnancy.

Canned vs Fresh Tuna: What is Safer?

Many pregnant women assume fresh tuna is "healthier" than canned, but from a mercury perspective, canned light tuna is often the safer choice.

Canned Tuna

• Typically uses smaller, younger skipjack tuna with lower mercury accumulation
• Undergoes heat processing that eliminates bacterial concerns
• More affordable and convenient for regular consumption
• Pro tip: "Chunk light" on the label usually means skipjack (lower mercury). "Solid white" or "albacore" means higher mercury—enjoy less often.

Fresh Tuna Steaks

• Often cut from larger yellowfin or bigeye tuna with higher mercury levels
• Must be cooked thoroughly (opaque throughout) during pregnancy
• Avoid raw or rare preparations (sashimi, tartare, poke bowls)
• Restaurant tuna steaks may be seared rare—always request well-done

Knowledge Check: Test Your Understanding

What About Sushi-Grade Tuna?

This is a common question, so let us be clear: raw tuna should be avoided during pregnancy, regardless of its "sushi-grade" designation. The term "sushi-grade" is actually a marketing term with no regulatory definition—it does not guarantee safety from parasites or bacteria.

If you are craving Japanese food, opt for:

• Cooked shrimp or crab rolls
• Vegetable rolls (cucumber, avocado)
• Grilled salmon teriyaki bowls
• Tempura options (fully cooked)

Lower-Mercury Alternatives for Omega-3s

If you want to reduce your tuna intake while still meeting omega-3 needs, these alternatives offer similar DHA benefits with even lower mercury:

• Salmon (wild or farmed): 0.022 ppm mercury—one of the lowest
• Sardines: 0.013 ppm mercury, plus bonus calcium from edible bones
• Anchovies: 0.017 ppm mercury
• Trout: 0.071 ppm mercury
• Pollock: 0.031 ppm mercury (commonly used in fish fingers)

Practical Meal Ideas

Here are pregnancy-safe ways to enjoy tuna:

• Classic tuna salad: Canned light tuna with pasteurised mayo, celery, and lemon on whole-grain bread
• Mediterranean tuna bowl: Tuna, white beans, olives, cherry tomatoes, and olive oil dressing
• Tuna pasta bake: Mixed with cooked pasta, vegetables, and pasteurised cheese—served piping hot
• Tuna fishcakes: Pan-fried until golden and cooked through—great for meal prep

Storage and Safety Tips

• Store opened canned tuna in a sealed container in the refrigerator and use within 1-2 days
• Fresh tuna should be consumed within 1-2 days of purchase
• When reheating leftover tuna dishes, ensure they are steaming hot throughout
• Drain and rinse canned tuna lightly to reduce sodium content

Common Questions

• Can I eat tuna every day? Not recommended during pregnancy. Even with canned light tuna, daily consumption could exceed weekly mercury limits. Aim for variety with different fish types.
• Does cooking reduce mercury? No—mercury is not reduced or eliminated by cooking, freezing, or any preparation method. Portion control is the only way to manage exposure.
• What if I accidentally ate too much? Do not panic. Occasional excess is unlikely to cause harm. Simply reduce intake over the following week. If you are concerned, speak with your midwife or GP.
• Are tuna pouches different from cans? Nutritionally similar. Check whether it is skipjack (light) or albacore (white) and follow the same guidelines.

The Bottom Line

Tuna can absolutely be part of a healthy pregnancy diet when consumed mindfully. Choose canned light tuna most often, limit albacore to once weekly, and avoid raw preparations. Combined with other low-mercury fish like salmon and sardines, you will give your baby excellent omega-3 nutrition without unnecessary mercury exposure.

Remember: the goal is not to fear fish, but to eat it wisely. Your baby's developing brain will thank you for those DHA-rich meals.

Related Reading

See also: Is Salmon Safe in Pregnancy?, Is Sushi Safe During Pregnancy?, and Foods to Avoid During Pregnancy.

Download PregnancyPlate to track your weekly fish intake, monitor mercury exposure, and get personalised omega-3 guidance based on your pregnancy stage.